1. Field of the Invention
The invention relates to organopolysiloxanes comprising quaternary ammonium groups and the preparation and use of the organopolysiloxanes.
2. Description of the Related Art
U.S. Pat. No. 3,389,160 (corresponding to DE 1 493 384 B) describes quaternary ammonium pendant siloxanes which can be prepared by reacting appropriate epoxyalkylsiloxanes with secondary amines and subsequent quaternization of the resulting tertiary amine groups with alkylating agents such as methyl chloride.
U.S. Pat. No. 4,895,964 describes a further development of the process described in U.S. Pat. No. 3,389,160 wherein, instead of the secondary amine, a salt of a tertiary amine is used for reacting the epoxysiloxane and, in addition, a catalytic amount of a free tertiary amine is added, this catalytic amount having a ratio of from 0.0005:1 to 0.05:1 for free tertiary amine equivalent to tertiary ammonium salt equivalent. The production process accordingly requires the use of two reagents: tertiary ammonium salt and free amine. If, for reasons of better dispersibility, the ammonium salt were prepared in situ, by adding the amine before the acid, the required low concentrations of free amine necessitate very accurate control over the amount of acid added, which is scarcely achievable in industrial practice.
Branched organopolysiloxanes having quaternary ammonium groups are disclosed in EP 1 561 770 A. The branched quat siloxanes are obtained by combining siloxanes having lateral epoxy groups and α,ω-epoxysiloxanes with tertiary mono-and diamines. This complicated multicomponent technology requires very precise fine-tuning of the reactant quantities and is not very tolerant with regard to the quality of the lateral epoxysiloxane as far as the number and concentration of its epoxy groups are concerned. The products are free of epoxy groups, since the organic radical E in question is defined in paragraph [0038] of EP 1 561 770 A such that it bears exactly one quaternary nitrogen atom.